Billions of syringes are made every month around the world. And by changing a part of the existing disposable syringe mold, Koska designed a mechanical valve into the plunger that passes through the inside of the barrel.

A small ring etched on the inside of the barrel allows the specially-adapted plunger to move in one direction and not the other.

After one complete injection is given, the plunger automatically locks in place. If you use excessive force to try to retract the plunger, the plunger snaps and the syringe can't be used anymore.

Koska set up the medical technology company Star Syringe to manufacture the auto-destruct. It can be incorporated costs the same as the standard disposable syringe.

The Tanzanian government has agreed to use only non-reusable types of syringes. According to Koska, they recognized the problem: they don't have enough sterile syringes, those are being reused probably 4 or 5 times each, and this reuse is a massive contributor to their burden of healthcare.

The country will probably go from using 40 million syringes to 200 million – that’s about $7 million extra, though it’s likely to save them $70 million in healthcare costs, Koska says.